Electric meter.



T. DUNCAN.

ELECTRIC METER.

(Application led eb. 7, 1898.)

(No Modem -M 3 Sheets-$heet l.

In. 698,637. Patented Apr. 29, |902.

No. '698,631 Patented Apr. 29, |902.

T. DUNCAN.

ELECTRIC METER.

(Application filed Feb. 7, 1898.) (No Model.) 3 sheets-sheet 2.

wi/13 wao/.MEO A M gn MO j @13 aflora/udg T'HE noms Evans /oxp'nuromno., wAsmNnTon, n. c.

No. 998,637. Patenmd- Apr. 29, |902.

- T. nuNcAN.`

ELECTRIC METER.

(Application med Feb. 7, 189s.) (un Model.) 3 sheets-sheet 3.

Fig. 5.

UNITED STATES PATENT OEETCE.

TIIOMAS DUNCAN, OF FORT WAYNE, INDIANA, ASSIGNOR TO rII-IE SIEMENS du HALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

ELECTRIC M ETER.

SPECIFIGATION forming part of Letters Patent No. 698,637, dated April 29, 1902.

Application iiled February '7, 1898. Serial No. 669,383. (No model.)

To all whom it 12v/ay concern.-

Beit known that I, THOMAS DUNCAN, a citizen of the United States,'residing at Fort Wayne, in the county of Allen, in the State of Indiana, have invented certain new and useful Improvements in Electric Meters; and

I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the lo art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form part of this specification.

My invention relates to improvements in i5 integrating wattmeters for the measurement of alternating electric currents and belongs t0 that class known as integrating motormeters. l s The object of my present invention is `to 2o provide an improved method of and means for accuratelymeasuring the energy expended on both inductive and non-inductive loads in alternating-current systems of distribution.

Another object of my invention is to secure such an arrangement of the actuating parts that the magnetism representing the e1ectromotive force will lag ninety degrees behind the impressed electromotive force.

My invention comprises a series field carrying the main current, a compound shunt-` coil representing the electromotive force in volts, a revoluble armature of the closed-circuit type arranged ininductive relation to the alternating magnetic fields of said series and volt-coils and adapted to be actuated thereby, a transformer supplying currents to the compound volt-coil, and means for adjusting the self-induction of the coils composing the said volt-coil.

4o Similar reference-numerals indicate like parts throughout theseveral` viewsof the drawings,which are diagrammatic views illus trating the relation ot' the actuating parts of the meter. y

Figure l shows a disk-like armature in inductive relation to two alternating magnetic fields, consisting of a series coil and a compound volt-coil. Fig. 2 shows a resistance in series with one of the coils forming the com- 5o pound volt-coil, which may be employed in conjunction with the resistance in the other coil of said volt-coil to adjust their resultant magnetism. Fig. 3 shows a form of transformer adapted to regulate the speed and accuracy of the meter by means of a separable adjustable part, forming a part of the magnetic circuit. Fig. .L shovvs the adaptation of my improvement to a three-Wire system of distribution. Fig. 45 shows a modified arrangement of the series and volt coil and a starting- 6o coil to overcome friction in series with a noninductive resistance whereby its current will be in phase with the line electromotive force. Fig. 6 shows a cylindrical armature, as seen in Fig. 5, arranged Within the series and volt co1 s.

Between the series coils 3 and the compound volt-coils 5 and 6 and in inductive relation i thereto the armature 4 is revolubly mounted,

being rigidly iiXed to a proper shaft 4, adapted 7o to rotate in suitable bearings. The armature 4 may bea thin diskA of aluminium or other metal ot proper conductivity, Figs. l, 2, 3, and 4, or it maybe in the form of a cylinder, as shown in Figs. 5 andG. To the upper end of 75 ,the armature-shaft 4pC suitable counting or reg- `ot which represents the electromotive force in volts and which isformed 4of twocoils 5 and 6, the latter arranged within the former. 8 5 These coils 5 and 6 have their magnetic axes concentric with each other and in parallel and eccentric relation with the axis of the series coil, and they receive their current from the transformer 10. 1 9e The operation of myimproveillent is as follows: The current from the generator 1 is transmitted to the translating devices or y i lamps 2 in the work-circuit over the lines 2l and 22 and passing through 4the seriescoil 3. 95 in its path, thereby setting up in said coil a magnetic field proportional to the current strength. When the translating devices are incandescent lamps or other non-inductive transformers of energy, the current and magroo netism of the series coils will be approximately in step with the electromotive force of the source of current. The rotation of the armature is produced by the resultant shifting iield established by a diiference of phase between the magnetism of the series coil and that of the compound shunt-coil, the said field acting inductively upon said armature in a Well-understood manner.

The present practice ot" adding an inductive resistance in series with the volt-coil to give it the necessarylag behind the impressed electromotive force insures rotation of the armature proportional to the watts on noninductive loads, but makes such meters unreliable and inaccurate on inductive loads, such as motors. To remedy this defect and make the torque of the meter proportional to the energy or Watts ou inductive loads, or CKEX cosine of the angle of lag, the magnetism of the volt-coil must be in quadrature with the line electromotive force, and when the main current in the series coil is non-inductive it will be in phase with the line electromotive force, and both will be in advance of the magnetism of the said compound shuntcoil by ninety degrees, thereby accomplishing one of the principal objects of my invention. The coil 5 of said compound shuntcoil receives current from the supply-mains by being connected in series with the primary circuit 11 of the transformer 10 by means of the wires 12 and 13, andthe coil 6 receives current from the secondary circuit 14 of the same transformer by means or' the wires 15 and 16. The current owing through the primary 11 and coil 5 will lag behind the line electromotive force less than ninety degrees, and the current owing through the secondary 14 and the coil 6 will lag more than one hundred and eighty degrees, these currents iiowing, respectively, through the coils 5 and 6 of the compound volt-coil, which are adjusted with the resistances 7 and 9, thus producing a resultant magnetic field which is ninety degrees behind the line electromotive force. This resultant magnetic ield represents the pressure of the circuit, and since it lags ninety degrees behind the magnetism of the series coil when the latter is non-inductive a shifting eld is established between the magnetism of the series coil and the resultant magnetism of the said coils 5 and 6, which thereby actuates the revoluble armature. The torque exerted with a given number of amperes and volts will depend upon the cosine of the angle of lag and will be proportional to the sine of the angle between the magnetism of the series or ampere coil and the resultant magnetism of the coils 5 and 6 with any given rate of alternations. If the resulting magnetism of the coils 5 and 6 of the said voltcoil is in quadrature with the line electromotive force, then by passinga current through the series coil that lags, say, forty-tive degrees behind the line-pressure the torque eX- erted will only be .7071 of the apparent watts or proportional to the real watts. Should the current in the series coil lag ninety degrees behind the electromotive force no rotation of the armature will take place, for the obvious reason that the series and shunt fields would then be in phase with each other, and no shifting actuating field will result. As a means for varying the self-induction of the coil 6 I employ a resistance 7. In Fig. 2 is shown another resistance 9 in series with the coil 5 and also a laminated iron core 8 in the compound Volt-coil for adjusting the lag and rate of speed.

In Fig. 3 is shown a modified form of transformer having a separable piece 17, forming part of the magnetic circuit and adapted to be adjusted to any suitable distance to or from the poles of the U-shaped core of the coils 1l and 14. This ligure also shows the series coil operating in a series circuit supplying the lamps 2.

In Fig. 5 the armature is of the cylindrical type, and the series and volt coils are shown diametrically at 3, 5, and 6. The resultant magnetism of 5 and 6 represents the pressure in volts. Fig. 5 also shows diametrically a shunt coil or winding 18 used to produce an initial starting torque for overcoming the friction. This coil 18 is in series with a noninductive resistance 19, whereby its current will be in phase with the line electromotive force.

Having thus described my invention, what I desire to secure byLetters Patent is 1. In an induction motor-meter, the combination with the series held-winding, of an armature in inductive relation therewith, a shunt field-winding also in inductive relation with said armature, said shunt held-winding comprising two coils and a transformer, the primary o f said transformer being included in series with one of said pressure-coils and connected therewith across the circuit-mains, the secondary of said transformer being closedcircuited through the second pressure-coil, and a centrally-located core aboutwhich said pressure-coils are placed and aording the only path of magnetic material for the pressure lines of force to vary the magnetic flux dueto said shunt-coil, threading the armature, an adjustment of said core toward the armature serving to delect an increased number of lines of force through the armature,` substantially as described.

2. In an induction motor-meter, the combination with a series field-winding, of an armature in inductive relation therewith, a shunt field-winding also in inductive relation with said armature, said shunt field-winding comprising two coils, a transformer, and means for varying the length of the magnetic circuit of said transformer, the primary of said transformer being included in series With one ot said pressure-coils and connected therewith across the circuit-mains, the secondary of said transformer being closed-circuited through the second pressure-coil, and a centrally-lou IOO tto

Iig

cated core about which said pressure-coils are placed, aording the only path of magnetic material for the pressure lines of force to vary the magnetic iiuX due to said shunt-coil, threading the armature, an adjustment of said core toward the armature serving to deiiect an increased number of lines of force. through said armature, substantially as described.

3. In an induction motor-meter, the combination with a series field-Winding, of an armature in inductive relation therewith, a shunt fleld-winding also in inductive relation with said armature, said shunt field-winding com-A prising two coils, a transformer, and means for varying the length of said transformer, the primary of said transformer being included in series with one of said pressure-coils and connected therewith across the circuit-` mains, the secondary of said transformer being closed-circuited through the second pres` sure-coil, a centrally-located core about which said pressure-coils are placed, affording the only path of magnetic material for the pressure lines of force, to vary the magnetic ux due to said shunt-coil threading the armature,- an adjustment of said core toward the armature serving to deflect an increased number of lines of force through said armature, and adjusting resistancesincludedin said primary and secondary transformer-circuits, substantially as described. i

4. In an induction motor-meter, the combination with a series held-winding, of an armature in inductive relation therewith, a shunt field-winding also in inductive relation with said armature, said shunt field-winding comprising two coils, atransformer, and means i for varying the length of said transformer,

the primary 4of said transformer being in` eluded in series with one of said pressure-coils and connected therewith across theV circuitmains, the secondary of said transformer being closed-circuited through the second pressure-coil, a centrally-located core about which said pressure-coils are placed, affording the only path of magnetic material for the pres sure lines of force to vary the magnetic flux d ue to said shunt-coil,threading the armature, an adjustment of said core toward the arma ture serving to deiiect an increased number of lines of force through said armature, the said core being so proportioned that a large air-gap intervenes between the same and the said coils, and adjusting resistances included in said primary and secondary transformer-l circuits, substantially as described.

Signed by me at Fort Wayne, Allen county,

State of Indiana, this 31st day of January,`

A. D. 1898. l y y THOMAS DUNCAN. Witnesses M. G.WEBBER, GnAs. C. MILLER. 

